For decades, one golden rule has guided America's military involvement in Africa: Stay out.

Generally speaking, the reason was a sense that the strategic stakes did not justify the risk. When we deviated from this rule, we often learned lessons the hard way that seemed to reinforce its validity, as in Somalia in 1993. And while presidents often profess a stronger interest in Africa than their actions would imply, they tend to say such things when not in the White House — witness Bill Clinton calling the nonintervention in Rwanda's 1994 genocide his greatest regret as president, or Sen. Barack Obama calling for more assertiveness in the Democratic Republic of Congo, or DRC, and Sudan six to eight years ago.

But, in fact, now is the time to reassess this long-standing American anathema to military involvement in Africa's terrible wars.

At a time of national war fatigue and fiscal austerity, it may be counterintuitive to propose an increase in U.S. involvement — particularly military commitment — abroad. And given the problems that continue in Somalia, Kenya, Mali, Libya, Sudan, the DRC and Nigeria, Africa does not appear to be an area of opportunity. But, for a modest investment, the U.S. and other countries may be able to make major strides toward improving the prospects for peace and stability on the continent.

France is doing important work in Mali and the Central African Republic, and the European Union is planning to help in the latter conflict as well. Most impressive of all, the African Union, led by states such as South Africa, Ethiopia, Kenya and Uganda, is making a major difference in Somalia, the DRC and beyond.

But rather than view that as an excuse not to be involved, the United States should seize the opportunity to contribute to a greater international effort to help turn Africa gradually from a zone of conflict to a zone of hope. Doing so will be good for America's own security and economic interests, as well as humanitarian ones.

Specifically, the United States could deploy a brigade combat team or one to two security force assistance brigades, or SFABs, making for a total of roughly 5,000 U.S. troops, to the DRC. This would beef up the existing U.N. peacekeeping force of just under 20,000 and give it the capacity to help the DRC get on its feet. The SFAB concept, developed in Iraq and Afghanistan, minimizes the combat role for U.S. forces while maximizing their mentoring and training roles (they can also help with logistics support).

The DRC mission has had recent successes but remains seriously under-resourced and under-equipped; fewer than 20,000 international troops are attempting to aid a country with twice the population and several times the land area of either Iraq or Afghanistan.

In addition, the U.S. could deploy up to several hundred Americans as part of a coalition team to train and mentor Libyan security forces so that Libya, which seemed a successful part of the Arab Spring when Moammar Kadafi was overthrown in 2011 but has since descended into chaos, can return to a more successful path. The real regret about Libya should center less on Benghazi — a tragedy to be sure but a limited one in strategic terms — and more on the fact that we are losing a chance to build stability in this small but hardly insignificant state.

Some view Africa as a continent forever mired in poverty and conflict. But over the last few years, several hopeful signs have emerged there. Healthcare has progressed, with tangible headway against HIV/AIDS. Continent-wide, the annual economic growth rate has averaged 4% in real terms for a decade. A number of countries — roughly a third of the continent's total — are showing significant progress in democratic and economic reforms. Civil wars in West Africa and southern Africa have subsided; estimates of overall death rates from conflict on the continent are at their lowest since the 1970s. The French intervened successfully to support a democratically elected leader in Ivory Coast in 2011. Even Sudan and Somalia have shown progress of late, albeit limited and fragile.

The U.S. can build on this fragile progress and make a significant contribution to its counter-terrorism and humanitarian agendas in Africa with relatively modest effort. We have already deployed a small contingent to help Uganda pursue the Lord's Resistance Army, while maintaining special operations forces in Djibouti to pursue Al Qaeda. The focus of this expanded effort should work through the U.S. Africa Command to build capacity in African states through programs such as the Global Peace Operations Initiative and the Trans-Sahara Counterterrorism Partnership.

Consider again the DRC. Despite the creation of a rapid reaction brigade in recent months to strengthen the U.N. presence and take on militias such as the M23 group, Congolese forces remain weak. The general absence of the state in all domains of life will continue to compromise the very survivability of vulnerable groups such as the young, the elderly, the diseased and childbearing women. More than 3 million people are believed to have died in the eastern part of the country since the mid-1990s.

The best path toward a more hopeful future is a systematic effort by the United States and other outside powers to strengthen and reform Congolese security forces. This requires a deployed force on the ground such as a brigade combat team or an SFAB.

In Libya, the real strategic loss has been a missed opportunity to help strengthen and stabilize the new government. This mission need not be particularly large or costly. But the minimalist approach that the international community has followed has left the country worse off than it was under Kadafi. Militias roam the streets; oil production and national GDP are way down; institutions, including those providing education and healthcare, are barely functional.

As part of a larger international effort, several hundred American troops in a training role could make a major difference. In so doing, they could also help reduce the spillover risks posed by renegade and extremist groups to neighboring countries such as Mali, Tunisia and Algeria.

To be sure, any stepped-up military involvement — by U.S. forces and/or other countries — needs to be carefully designed and implemented. But in countries such as the DRC, the forces needed would be modest enough in scale that such an initiative would not be incompatible with the Asia-Pacific rebalance, ongoing defense budget cuts or even a modestly stepped-up American role in Syria.

And for a U.S. president struggling to find workable big ideas to inspire his presidency and the nation, Africa may counterintuitively be a promising place to look.

Michael O'Hanlon is a senior fellow at the Brookings Institution and the author of "Healing the Wounded Giant: Maintaining Military Preeminence While Cutting the Defense Budget."